Discharge valve for a container



1968 R. K. KRETZSCHMANN 3,403,835

DISCHARGE VALVE FOR A CONTAINER Filed Jan. 12, 1967 FIG.|

FIG. 2

RICHARD Kv KRETZSCHMANN INVENTOR.

BY (Z/mf/ 0/ 01% ATTORNEY United States Patent 3,403,885 DISCHARGE VALVE FOR A CONTAINER Richard K. Kretzschmann, Salt Lake City, Utah, assignor to Hercules Incorporated, Wilmington, DeL, a corporation of Delaware Filed Jan. 12, 1967, Ser. No. 608,808 8 Claims. (Cl. 25163.5)

ABSTRACT OF THE DISCLOSURE This application relates to a discharge valve designed for use in a mixing tank for slurry explosives, the valve being characterized in that it has a face that is flush with the inner surfaces of the tank, has a straight through discharge path with no pockets, and has no metal-to-metal contact in any area exposed to the explosive. In this manner, there is no spot where the explosive can be deposited to avoid mixing, there is a discharge path that offers a minimum of resistance to flow of the slurry, a minimized danger of accidental detonation during operation of the valve or dismantling of it for cleaning.

The present invention relates to a discharge valve adapted to be mounted in the Wall of a container and particularly to a valve for use in a mixing bowl for an explosive slurry.

It is an object of this invention to provide a valve adapted to be mounted on the wall of a container and to seal a discharge opening therein without protruding into the container 'beyond the inner surface of the wall whereby it will not interfere with the operation of the mixing element or other mechanism or operating elements within the container.

A further object of this invention is to provide a valve which is adapted for use with slurry explosives in that it has no metal-to-metal contact in any area that comes into contact with the explosive, has no dead spaces or pockets in which slurry could be deposited or accumulate, or which cannot be readily and completely cleaned, has a smooth flow which does not involve any sharp turns and which thus requires less force to drain the slurry through the valve and insures a more complete and more rapid discharge from the container, and which can be readily and completely dismantled for cleaning.

Another object of this invention is to provide a valve which is compact and is therefore adapted to be used with existing equipment where there are space limitations and which, although compact, provides positive alignment of the valve so that it will seat true when closed.

Further objects of this invention are to provide a valve in accordance with the preceding objects, which is also relatively inexpensive, dependable, and trouble-free in operation, eflicient, and can be reliably actuated remotely.

Additional objects of this invention will be apparent from an understanding of the preferred embodiment of the invention hereinafter described with reference to the accompanying drawings, in which:

FIG. 1 is a fragmentary view in section of a valve constructed in accordance with this invention and mounted upon the discharge opening of a container.

FIG. 2 is a sectional view taken substantially on the line 2-2 of FIG. 1.

With reference to the drawings, there is illustrated a fragmentary portion of the wall 1 of a container having an opening 2 adapated to be closed by a valve 3 constructed in accordance with [this invention. While, as will be apparent, the present invention is not specifically limited thereto, the valve 3 has been designed primarily for use with a discharge opening in a mixing bowl for slurry explosives wherein a mixing element or blade has a motion 3,403,885 Patented Oct. 1, 1968 in which it passes closely adjacent to the inner surface 1a of the wall of the bowl and therefore cannot be accommodate a valve having any parts protruding inwardly from the inner surface 1a of the wall, and which mixing bowl requires a valve having a sealing surface that is flush with the inner surface of the wall and does not provide pockets above the valve in which slurry could be deposited and thus avoid mixing or could interfere with the operation of the valve 3. Accordingly, the inner surface 1a of the wall 1, which is at the inside of the container, is smooth and continuous and the valve 3 is adapted to seal the opening 2 flush with the inner surface 1a of the wall.

Depending from the wall 1 is a sleeve 4 having a bore 5 that is coaxial with but enlarged relative to the opening 2 and which communicates therewith by a tapered bore 6 in the wall 1. At its lower end, the sleeve 4 is formed with an outwardly directed flange 7 to which a flange 8 at the upper end of the valve housing 9 is secured by means of a split clamp 10 having the opposite halves thereof secured together by bolts 11. The valve housing 9 has a bore 12 that corresponds in diameter to the bore 5 of the sleeve 4 and is accurately aligned therewith by a fibrous alignment ring 13. A gasket 14 and packing 15, which may be of rubber and polyethylene, respectively, or other suitable material, are interposed between the mating surfaces of the clamp 10 and the flanges 7 and 8 not only to provide a tight seal but also to eliminate metal-to-metal contact.

At its lower end, the valve housing 9 is provided with a second outwardly directed flange 16 to which a discharge conduit 17 is connected by means of a clamping disc 18 that is secured to the flange 16 by a split clamp 19 similar to the clamp 10 and having the opposite halves thereof secured together by bolts 20. Also, like the clamp 10, a gasket 21 and packing 22 are interposed between the flange 16, clamping disc 18 and clamp 19. The conduit 17 is secured to the disc 18 by a ring 23 opposed to the clamping disc 18 and clamped thereto by bolts 25, there being a flange 24 at the upper end of the tube 17 that is disposed between the ring 23 and disc 18. The disc 18 has a bore 26 that is coaxial with and substantially equal in diameter to the opening 2 and is in direct communication with a bore 27 of equal diameter in the bottom of the valve housing 9. The 'bore 27 in turn communicates with the enlarged bore 12 of the valve housing 9 by means of a tapered bore 28. The bore 29 of the conduit 17 is also substantially equal to the diameter of the bore 26.

A valve cup 30 is supported internally of the valve housing 9 by a bracket 31 and a pair of spaced supports 32 (FIG. 2), all of which extend inwardly from the wall of the valve housing at the tapered bore 28. The cup 30 is mounted in the enlarged bore 12 of the valve housing 9 with the open end of the cup facing toward but spaced from the opening 2 in the wall 1 and with the periphery of the cup 30 spaced from the opposed walls of the housing to provide an annular flow path 33 about the same. More particularly, the cup 30 comprises a bottom wall 34 and a cylindrical side wall 35 upstanding therefrom and arranged coaxial relative to the opening 2 in the wall 1. A valve head 36 has a shank or stem 37 mounted in the cup 30 for endwise sliding movement, there being a bushing 38 interposed between the shank 37 and the inner surface of the side wall 35 of the cup 30, which bushing is preferably of an anti-friction material such as Teflon. The bushing 38 serves to avoid metal-to-metal contact between the opposed surfaces of the shank 37 and side wall 35, as well as to reduce sliding friction between them. The bushing 38 has an outwardly directed flange 39 at the top thereof, overlying the top or free edge of the side wall and is adapted to engage the bottom wall of a laterally projecting flange 41 on the valve head 36 to limit the downward movement of the head 36 in the cup 30. When the valve head 36 is at its lowermost position in the cup 30, the bottom face 42 of the stem 37 is spaced slightly from the top surface of the bottom wall 34 of the cup 30.

The valve head 36 also includes a skirt 43 depending from the outer edge of the fiange 41 in spaced relation to the periphery of the stem 37 by an amount sufficient to accommodate the combined thickness of the side wall 35 of the cup 30 and the sleeve 38 whereby the skirt 43 cooperates with the outer face of the side wall 35 to guide the head 36 and to receive an O-ring 44 between the cooperating surfaces to form a seal that prevents both the escape of air pressure from and the penetration of slurry mixture into the valve.

The valve head 36 has an upper or sealing surface 46 which conforms in outline to the shape of the opening 2 in the wall 1 and which acts to close the opening 2. In surface configuration the upper surface 46 conforms to the inner surface 1a of the Wall 1 so that, when the valve is closed, the upper surface provides a smooth continuation of, or in other words is flush with the inner surface 1a of the Wall. Accordingly, in the embodiment illustrated in FIG. 1, in which the inner surface 1a of the wall is fiat, the upper surface 46 is also flat. The upper surface 46 of the valve head 36 is surrounded by a seating surface 47 that is inclined relative to the surface 46 at an angle corresponding to the angle of inclination of the tapered bore 6 of the Wall 1 and against which it is adaped to seat. The upper surface 4-6 and seating surface 47 of the valve head 36 are covered by a cap 48 that is formed, by example, of rubber, and which has an inwardly directed rib 49 at its free edge that is adapted to seat in a peripheral groove in the outer face of the skirt 43.

To prevent the slurry mixture from coming into contact with the relatively sliding surfaces of the valve head 36 and the side wall 35 of the cup 30, there is provided a resilient sleeve 50. While the details of the sleeve 50 are not critical to this invention, it is in the illustrated embodiment formed of rubber and is adapted to form a continuation of the cap 48. For securing the sleeve 50 in place, it is provided with an inwardly directed rib 51 that is adapted to seat in a peripheral groove in the outer face of the skirt 43 and which thus anchors one end of the skirt while the other end thereof is anchored to the cup 30 by a second inwardly directed rib 52 that engages under the shoulder at the bottom of a rib 53 on the outer face of the side wall 35 of the cup 39. It will of course be obvious that the sleeve 50 could be formed of any flexible and impervious material such as metallic bellows-like material and that the opposite ends of the sleeve could be secured respectively to the skirt 43 of the valve head 36 and to the cup 30 in a different specific manner, for example, by cooperating threads molded into the sleeve and formed on the cup 30 and skirt 43 of valve head 36.

In order to actuate the valve 3, that is, to move the valve head 36 between its closed and opened positions, there is provided a nipple 54 that is aligned radially of the valve housing with the bracket 31 and a bore 55 that extends through the nipple 54 and the bracket 31 and intersects the inner chamber 56 of the cup 30 at the bottom wall 34 thereof. The nipple 54 is connected by a conduit 57 to a source of fluid, e.g., air under pressure. The valve stem 37 of the valve head 36 is also provided with a plurality of bores 58 from the bottom surface 42 thereof to a point adjacent the bottom wall 40 of the flange 41. Thus, pressure introduced into the chamber 56 is also conducted through the bores 58 to the closed space between the periphery of the stem 37 and the skirt 43 and above the flange 39 of the bushing 38 whereby the pressure is applied over an increased area to increase the 4 total force biasing the valve head 36 to its closed position and also acts to prevent slurry leaking into the closed space.

In operation, the valve 3 is held closed as illustrated in FIG. 1, by fluid under pressure from a control point introduced into the chamber 56 through the conduit 57 and bore 55. With the valve closed, the upper surface thereof, that is, the upper surface of the cap 48 when a cap is used, is flush with the inner surface 1a of the wall 1 thereby permitting use in the mixing operation of a mixing blade that passes close to the inner surface 1a of the container. Such a mixing blade insures a thorough mixing of the material while the flush surface above the valve does not provide any pockets in which the material could be trapped and thus avoid mixing. After mixing, the chamber 56 is exhausted from the control point through the conduit 57 and the valve 3 thereby opened by the pressure produced by the combined weight of the valve head 36, the head of the material in the container, and the pressure differential that exists between the mixing bowl and the conduit 17. In opening, the stem 37 of the valve head 36 moves downwardly in the bushing 38 until the bottom wall 40 of the flange 41 engages the flange 39 at the top of the bushing 38. At this time, the bottom 42 of the stem 37 is spaced from the bottom wall 34 of the cup 30 and the free edge of the skirt 43 is spaced from the top of the rib 53 so that there is no nietal-to-metal contact. As the valve opens, the mixture in the container is discharged through the opening 2, through the annular space 33, about the periphery of the valve head 36 and cup 30, and through the conduit 17.

As the valve head 36 moves downwardly, the sleeve 50 relaxes but maintains a liquid tight seal over the relatively sliding surfaces of the side wall 35 of the cup 30 and the skirt 43 of the valve head 36. One of the advantages of a sleeve 50 formed of resilient material is that the sleeve can be stretched when the valve is closed so that when the valve opens, not only does the contraction of the sleeve 50 help to pull the valve open but the sleeve itself also contracts rather than folds. In this manner, there is provided a relatively smooth flow path for the contents of the container discharged through the valve.

One of the significant features of the invention is that there is no point in the valve itself in which any material can be trapped and which would present a safety hazard when handling explosive materials. The valve 3 is also adapted to be quickly removed from the container and to be thoroughly dismantled for purposes of cleaning. At no time is there any movable metal-to-metal contact in the presence of the explosive material, that is, either when the valve is opened to permit discharge of the material from the container or in removing the valve from the container or in dismantling it for cleaning. Neither are there any pinch points where explosive could be trapped. In this manner, the possibility of an accidental detonation of the explosive material is virtually eliminated.

The valve in accordance with this invention is also adapted for use in applications where sanitation is required, such as in the food industry. In such a case, the construction of the valve eliminates pockets wherein material can be trapped and from which it cannot be easily cleaned.

What I claim and desire to protect by Letters Patent is:

1. A valve for sealing a discharge opening in a wall having a smooth inner surface and a valve seat surrounding the opening, said valve comprising a valve housing having a discharge passage, means for mounting said valve housing relative to the wall with the discharge passage thereof in communication with the discharge opening in the wall, a cup mounted in the discharge passage of the valve housing with the open end thereof facing toward and spaced from the discharge opening and with the periphery thereof disposed in spaced relation to the wall of the discharge passage to provide an annular passageway about the periphery of the cup, a valve head having a valve stem slidably mounted in said cup for movement of said head between a closed position and an open position relative to said valve seat, said valve head having a seating surface adapted to cooperate with the valve seat when in the close-d position and having an upper surface internally of said seating surface and conforming in surface configuration to the inner surface of the wall whereby the discharge opening in the wall is sealed flush with the inner surface of the wall when the valve is closed, a skirt of a flexible and impervious material surrounding and secured at its opposite ends to said cup and valve head thereby providing a seal between the passage and the relatively sliding surfaces of said cup and valve head, and means for introducing fluid under pressure into said cup below the end of said stem for biasing said valve head toward its closed position and for exhausting the same to permit said valve head to move to its open position.

2. A valve in accordance with claim 1 in which the seating surface of said valve head has a resilient nonmetallic material whereby when the valve is closed there is no metal-to-metal contact between the valve head and the valve seat in the wall.

3. A valve in accordance with claim 1 in which the external diameter of the cup is less than the diameter of the passage by an amount such that the annular passageway about the cup is substantially equal in area to the area of the opening in the wall.

4. A valve in accordance with claim 1 in which there is provided a bushing internally of said cup and said stem is slidably received within said bushing.

5. A valve in accordance with claim 4 in which said bushing has a laterally extending flange overhanging the free end of the cup, said flange serving as a stop for defining the open position of said valve head and acting to prevent contact between said valve head and said cup.

6. A valve in accordance with claim 1 in which said valve head has a depending skirt disposed in spaced relation to said stem and adapted to cooperate with the periphery of said cup for guiding said valve head.

7. A valve head in accordance with claim 6 in which there is provided a bore through said stem from the fluid pressure chamber between the bottom of said stern and said cup to the space between said stem and skirt and above the edge of said cup.

'8. A valve in accordance with claim 7 in which there is provided a fluid pressure seal between the opposed surfaces of the skirt and the cup.

References Cited UNITED STATES PATENTS ARNOLD ROSENTHAL, Primary Examiner. 

